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Biomedical subjects

K Mizoi

Publications and source records attributed to K Mizoi.

At least 127 records · Page 7Linked to original sources
PubMed1981

[Experimental study of new cerebral protective substances--functional recovery of severe, incomplete ischemic brain pretreated with mannitol and fluorocarbon emulsion-- (author's transl)].

Using the "canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effects of mannitol (which acts as a free radical scavenger) and FC (which has 0.1 micrometer of average particle size and a high oxygen-carrying capacity) on cerebral ischemia were investigated. After pretreatment with the drugs, blood flow was reduced via the pump to 1/10 of the normal flow volume and 1 hr later, return to a normal flow was allowed. Subsequent changes in electrical activity were observed and the effects of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in the animals treated with either mannitol or FC, incomplete, yet distinct recovery was apparent. In the animals administered with mannitol together with FC, however, marked recovery was evident. These experimental results indicated that a combined administration of FC and mannitol is effective in protecting the brain from cerebral ischemia.

Animals↗
PubMed1981

[Development of new methods in suppressing brain infarction--combined administration of mannitol and perfluorochemicals (author's transl)].

Various therapeutic methods have been attempted for cerebral infarction, but the development of more effective methods is still awaited. We have investigations of the effect of mannitol in preventing the development of cerebral infarction and have reported it effects in clinical cases of operated cerebral aneurysms. In recent years, our attention has been drawn to the so-called red cell substitute, perfluorochemicals (FC), which has a high oxygen-carrying capacity and a small particle less than 0.1 mu. In the present studies, using infarction models in dogs which have previously developed and reported, observations are made on the recovery of brain electrical activity in sever ischemia, suppressing brain swelling following recirculation of cerebral blood flow and protection upon the hemorrhagic brain infarction, due to administration of mannitol or FC. These experimental results indicate that the combined administration of mannitol and FC is effective in protecting the brain from cerebral ischemia.

Animals↗
PubMed1981

[Subdural effusion following radical surgery for chiasmal region tumors in children--report of 4 cases (author's transl)].

Four cases of subdural effusion following radical surgery for the chiasmal region tumors in childhood were presented in this report. Three out of four cases were craniopharyngioma and the remaining one was optic glioma. The pathogenetic mechanisms of this disorder were explained probably and at least partly by a change from internal to external hydrocephalus or craniocerebral disproportion due to cerebral atrophy in two of the four cases and unclear in the remaining two cases. In all four cases meningitis did not supervene postoperatively. The subdural effusion may be divided into two types according to symptomatology, i.e., "serious type" which presents with severe symptoms and "mild-type" which is virtually asymptomatic. The serious type required immediate surgical procedure, such as continuous subdural drainage and subduroperitoneal shunt, while the mild type should be carefully monitored for the course of subdural effusion by CT scan.

Adolescent↗
PubMed1981

[Traumatic middle meningeal arterio-venous fistula--a case of bilateral occurrence (author's transl)].

A case of traumatic middle meningeal arterio-venous fistula was reported. The present case reported here appears to be unique because of its bilateral occurrence. As for traumatic middle meningeal arterio-venous fistula, we could not find any case with bilateral occurrence in the literature. Bilateral carotid angiograms revealed extravasation in the extradural spaces. Draining veins were found pouring into the superior sagittal sinus and also into the transverse sinus. This was also thought to be rare. We discussed to some extent on the etiology, diagnosis, angiographical findings and treatment of this disease.

Adult↗
PubMed1981

[Preservation of the olfactory tract following surgery on anterior communicating artery aneurysm using bifrontal craniotomy, and its functional prognosis (author's transl)].

Based upon 110 cases of AComA aneurysm approached via bifrontal craniotomy, we discuss preservation of the olfactory tracts and the functional prognosis for olfaction. (1) It is possible to preserve the olfactory tracts bilaterally or unilaterally in over 80% of such cases. (2) With regard to the correlation between surgical findings and subjective sense of olfaction, it was found that 47% of the cases with bilateral preservation, 34% with unilateral preservation and 33% of the cases with bilateral olfactory tract damage reported normal olfaction. (3) Objective examination of olfaction by an otolaryngologist showed that 84% of the patients reporting normal olfaction indeed had normal olfaction, whereas 91% of those reporting no olfaction were anosmic.

Cerebral Arteries↗
PubMed1980

Vector analysis of auditory brain stem responses (BSR) in human beings.

The purpose of the present study is to clarify the origins of BSRs. We recorded BSR by three ortho-diagonal leads (X-axis: right ear canal to left ear canal, Y-axis: vertex to submental position, Z-axis; forehead to inion). We studied the waveforms on each of the three planes: frontal, sagittal, and horizontal and analysed their vectors on the basis of Lissajous'figures. Lissajous'figures revealed the following: (1) The vector of wave I is almost horizontal and is directed towards the non-stimulated side. (2) Wave II seems to be derived from the cochlear nuclei and double firings of the auditory nerves. (3) Wave III represents the activities of the circuits of the auditory pathways in the brain stem. (4) The vector of Wave V is the largest of the five responses, and is directed towards the fronto-parietal region, tilting slightly to the non-stimulated side.

Adolescent↗
PubMed1980

[Changes of tissue pH in dog brain during ischemia--alkaline shift (author's transl)].

Brain pH changes during ischemia were observed by the newly established histochemical technique in Dr. Kogure's laboratory (Miami). The technique utilizes intravascular injection of neutral red as a pH indicator. Its use is based on the fact that neutral red is red in acid and yellow in alkaline pH. Thalamic infarction model in dogs was used in this experiment. The methods of producing this model by temporary occlusions of brain arteries have been published elsewhere. The animals were anesthetized with sodium thiopental, immobilized with pancronium bromide, and artificially ventilated with room air. Blood gases and blood pH were adjusted to normal. Before the experimental procedure, 3 ml/kg of a 5% saline suspension of neutral red was injected slowly into the femoral artery. After occlusions of cerebral arteries, the brain was frozen in situ by pouring liquid nitrogen into the bottomless cup. The frozen brain was mounted on a cryostat at -20 degrees C and sliced coronally in 10 micron thickness. Color differences in the serial sliced brain surface were observed. No change in the color was observed in the sham operated brains. Thirty minutes following occlusion, the color of the thalamus is reddish, and it was estimated that this area became acidotic. 1 hour following occlusion, too, the thalamus is acidotic. But 2 hour following occlusion, the color of the thalamus became yellowish, indicative of alkaline shift. From this experimental results, it is considered that the pH of ischemic brain changes dynamically, that is, ischemic brain becomes acidotic in the early stage of ischemia but with the lapse of time alkaline shift occurs.

Animals↗
PubMed1980

[A canine model of complete ischemic brain regulated with perfusion method (author's transl)].

A model of complete ischemic brain regulated with a perfusion method in dogs was produced by interrupting the main arteries at the base of the brain and perfusing the arterial blood from the femoral artery of the dog to the lt. hemisphere through a tube cannulated into the rt. M.C.A. retrogradely. The cerebral blood flow in the lt. hemisphere is regulated by the infused blood volume which can be regulated with a pump. Hyperemic brain, normal brain, incomplete ischemic brain and complete ischemic brain can be produced in the entire lt. hemisphere at will in all dogs. Recirculation is also possible by means of the regulation of blood flow after various degrees of ischemia. This model also allows for the study of the various effects of drugs on the ischemic brain and research on the sequential pathological and chemical changes without individual differences among the dogs. This model should be valuable for investigation of not only ischemia but also cerebral metabolism, cerebral pharmacology and cerebral blood circulation.

Animals↗
PubMed1979

The correlation between hypertension in past history and the incidence of cerebral aneurysms.

The incidence of hypertension in past history was investigated in 811 cases of cerebral aneurysm. These cases were compiled from 1,000 cases of saccular aneurysm in which direct surgical operations for aneurysm were performed at our clinic during the period from June 1961 to September 1975. Of the 811 cases, 365 (45%) had hypertension in their past history; 185 (42.7%) out of 433 males and 180 (47.6%) out of 378 females. In the 5th decade of age, the incidence was significantly higher in the females than in the males, but no difference by sex was noted in other age groups. In the males from the 3rd to the 7th decade, the number of hypertensives increased significantly with advancing age, whereas in the females a significant difference was observed only between the 4th and 7th decades, the latter including more hypertensives. The incidence of hypertensives in the aneurysm cases was compared with that in the Japanese population reported by Sasaki. This comparison revealed that in both sexes between the 4th and 6th decades, the incidence was significantly higher in the former, whereas no significant difference was noted between the two in the 7th decade. As to the location of aneurysms, only the multiple aneurysms group had a significantly greater number of hypertensives than single aneurysm group. These results agree with previous reports that cerebral aneurysm may occur more frequently in the hypertensives than in the normotensives.

Adult↗
PubMed1979

[Giant optic glioma--case report (author's transl)].

A 3 1/2-year-old girl with a huge optic glioma was reported. On February 26, 1978, she was hospitalized for signs of increased intracranial pressure, namely headache, vomiting and consciousness disturbance. Before admission she did not complain of her visual disturbance. A huge mass lesion in the subfrontal-suprasellar region was found by neuroradiological examination. The operation was performed on March 7, 1978, and the tumor arising from the right optic nerve, about 170 grams in weight, was totally removed in piecemeals. Histopathological diagnosis was pilocytic astrocytoma. Immediately after operation diabetes insipidus and hypernatremia developed, but two months later these symptoms disappeared. Post-operative CT scan demonstrated no mass lesion in the subfrontal-suprasellar region. After radiation therapy, she was discharged with slight left hemiparesis on August 31, 1978. Though her right eye was blind, visual acuity remained 0.2 in the left eye. No other neurologic deficits could be found.

Cerebral Angiography↗
PubMed1978

The development of a fibre optic catheter tip pressure transducer.

There has been much discussion on the distortion of intracardiac pressure waveforms measured by catheter methods. Tip transducers, which can eliminate this waveform distortion, have several problems. There are manufacturing difficulties with the mechano-electric transducing element. The devices also do not remain stable over variations in temperature and with long term clinical use. Safety problems may also be experienced due to the direct connection between external electronic devices and the heart. In order to overcome these difficulties, the application of fibre optics to the measurement of intracardiac pressure has been proposed. In this paper, the design, construction, and evaluation of a side-hole optic catheter, intended for intracardiac pressure measurement, is described.

Animals↗
PubMed1978

[Tethered cord syndrome--our three cases and the review of the literature (author's transl)].

Three cases of tethered cord syndrome are presented with reference of reported literatures. This syndrome is usually associated with spina bifida occulta and cutaneous manifestation such as subcutaneous tumor, skin dimple, hairy patch, and neavus. Presented symptoms are various progressive neurological deficits involving weakness and/or sensory disturbance of lower limbs, bowel and/or bladder dysfunction, leg and/or low back pain, and orthopedic pathological conditions such as scoliosis and/or foot deformities. Properly performed myelography is the only method of preoperative confirmation of this syndrome. As the surgical release of the tethered spinal cord is effective for these various symptoms except for foot deformity, early investigation and early surgery are recommended.

Abnormalities, Multiple↗
PubMed1978

[Angiographical study of ruptured aneurysm in the multiple aneurysm patients (author's transl)].

Sixty four multiple intracranial aneurysm cases have been analysed for the purpose of identifying the relation between aneurysm rupture and aneurysmal features, mass signs, vasospasms and locations of the aneurysms. 1) 85% of the larger and largest aneurysm in each case were the ruptured aneurysm. 2) Aneurysms with a greater ratio of length to width showed a high frequency of rupturing. 3) Irregularities of the aneurysmal wall and the existence of a daughter aneurysm attached to the main aneurysm have a tendency to rupture. 4) Evidence of mass signs, associated with intracerebral, subarachnoid and subdural hematoma or a cerebral edema is also useful for the identification of the ruptured aneurysm. 5) Anterior communicating artery aneurysms have a relatively high frequency of being the ruptured aneurysm in cases of multiple aneurysm. 6) By utilizing all the investigated factors of the angiogram, the ruptured aneurysm might be identified in about 90% of the cases of multiple aneurysms.

Adult↗
PubMed1978

[The angiographical study on cerebral vasospasm following the rupture of intracranial aneurysm (1st report).--Time relationship between vasospasm on angiography and the onset of subarachnoid hemorrhage (aurhor's transl)].

Time relationship between the presence of vasospasm on angiography and the onset of subarachnoid hemorrhage (SAH) was investigated with 797 direct surgical cases with intracranial saccular aneurysm. It has been said that vasospasm would occur in early days after the onset of SAH. But in this paper, in the cases with only one history of SAH, vasospasm occurred within 3 days after SAH was seen in only 4.2% of the 120 cases. The peak of vasospasm on angiography was seen in the period between 10 and 17 days after SAH. During this period vasospasm was seen in 49.1% of the 116 cases. Meanwhile, in the cases with preceding SAH occurred between 1 and 17 days before the onset of the last SAH, vasopasm occurred within 3 days after the last SAH was seen in 38.7% of the 62 cases. On the contrary, during the period between 10 and 17 days after the last SAH, vasospasm was seen in only 20% of the 25 cases. Preceding SAH occurred between 1 and 17 days before the last SAH seemed to be responsible for the high rate of vasospasm within 3 days after the last SAH and the low rate of vasospasm in the period between 10 and 17 days after the last SAH.

Adult↗